FR2625074A1 - MICROENCAPSULATED COMPOSITION FOR COMBATING BLATS - Google Patents

Abstract

Microencapsulated composition. It comprises phenylxylylethane and an insecticidal compound encapsulated in microcapsules having an average particle diameter of less than 80 microns and a wall thickness of less than 0.3 microns. Composition intended to fight against cockroaches.

Description

Microencapsulated composition for combating

cockroaches.

  The present invention relates to a composition

  microencapsulated assembly for combating cockroaches, in which an insecticide having a group

  3-phenoxybenzyl and phenylxylylethane are encapsulated

  in microcapsules with a polyurethane wall

  thanne which has a mean particle diameter not greater than 80 microns, a wall thickness which

  not more than 0.3 micron and a ratio of

  average meter of particles at the wall thickness

taken between 100 and 400.

  We fight against cockroaches mainly

  a residual spraying process.

  So far, formulations, such as emulsifiable concentrates, solubilized emulsion concentrates and oily solutions, which contain, for example, an organophosphorus insecticide or a pyrethroid insecticide as an active ingredient

  are used for residual spraying.

  Residual efficiency and safety are

  particularly desirable qualities for

  used for residual spraying. Yes

  we want to increase the residual efficiency of the formulas

  such as a concentrated emul-

  sionnable, a concentrated product in solubilized emulsion

  and an oily solution, an im-

  bearing that can pose security problems. There is a growing demand for safer formulations and

of great efficiency.

  In these circumstances, more and more research and development of the so-called microencapsulation technique, in which an ingredient

  active is enclosed in wall material.

  As microencapsulated insecticides, those containing an organophosphorus insecticide as an active ingredient are described in the published Japanese patent application.

  62-161706 and those containing insecticides

  pyrethroid acid as an active ingredient are described in

  the Japanese patent application placed under public inspection

than under No 55-38325.

  In some cases, microencapsulation of insect

  Ticides can be effective in improving residual efficacy.

  But the residual efficacy of insecticides half

  croencapsulated depends on the particle diameter of the

  microcapsule and the thickness of the wall. You have to choose

  the optimum particle diameter and wall thickness to maintain residual efficiency during

  an extended duration. This optimum range varies, although

  tended, depending on the type of pest against

  which one must fight with the help of the insecticides.

  In general, the microencapsulation of insecticides

  having a polyurethane wall is carried out by polymerisation

  interfacial assay using a polyfunctional isocyanate

tional.

  The interfacial polymerization process required

  essentially a stage of homogeneous mixing of an ingredient

  active ingredient, intended to be enclosed in capsules,

the polyfunctional isocyanate.

  In the case where the active ingredient is an insect

  ticide pyrethroid, we can add an organic solvent called co-solvent when the insecticide is mixed with a polyfunctional isocyanate viscosity sometimes large,

  since this insecticide usually has high visco-

  sity and is sometimes in crystalline form. Japanese Patent Application Laid-Open No. 55-38325 mentions "for example, as conventional organic solvents, hydrocarbons such as xylene, toluene, hexane and heptane can be selected. fluorinated hydrocarbons such as carbon tetrachloride and chloroform, ketones such as

  methyl isobutyl ketone, methyl ethyl ketone and cyclo-

  hexanone and esters such as diethyl phthalate

and normal butyl acetate ".

  But these known techniques are not necessary.

  satisfying when using certain insecti-

  Pyrethroid cides as an active ingredient to fight

against cockroaches.

  The inventors carried out extensive research

  on the optimum ranges of particle diameter and wall thickness of the microcapsules and on the selection of the best organic solvents when encapsulating an insecticide having a 3phenoxybenzyl group as the core material in a polyurethane wall and when using this capsule to fight against cockroaches. It has been found that certain insecticides having a 3-phenoxybenzyl group are microencapsulated as a core-forming material in a polyurethane wall and using phenylxylylethane as cosolvent,

  have residual efficacy for a prolonged period of time

  to fight against cockroaches.

  The present invention aims at a micro-composition

  encapsulated for combating cockroaches, hereinafter referred to as "the present composition", in which phenylxylylethane and at least one ingredient

  defined above are encapsulated in a micro-

  capsule having a polyurethane wall which has a diameter

  average of not more than 80

  crons, a wall thickness that is not superior

  at 0.3 micron and a ratio of the average diameter of

  the active ingredients mentioned above are those of the formula: X J

Y -CH 0

  R1 wherein R1 represents a hydrogen atom or a fluorine atom, X represents a hydrogen atom or a cyano group, and Y represents a group of formulas R2

C - CH-C-O-, (1)

R3 C

%

CH3 CH3

  wherein R2 represents a hydrogen atom or a methyl group; when R2 is a hydrogen atom, R1 represents a group of formula

4 R6

  -CH = C R or a group of formula / C-CH-, in which R4 represents a methyl group, in which R 4 represents a methyl group, a chlorine atom, a bromine atom or a fluorine atom,

  R5 represents a methyl group, a trifluoro-

  methyl, a chlorine atom, a bromine atom or a fluorine atom, R6, R7, R8 and R9, which are identical or different, represent a chlorine atom, a bromine atom, or a fluorine atom and, when R is methyl, R is methyl; a

  group represented by the formula: -

CH3 t XCH

R10 CH (2)

CH-C-O -

  Wherein R 1 represents a chlorine atom, a bromine atom, a fluorine atom, a trifluoromethoxy group,

  a trifluoromethoxy group, or a 3,4-methylene group

  dioxy, or a group represented by the formula: R12 R ilI (3)

C-CH2-Z. Z (

  In which Z represents an oxygen atom or a -CH 2 group, R 1 is a lower alkoxy group (it is in particular an alkoxy group having, for example, from 1 to 5 carbon atoms), a chlorine atom, a

  a bromine atom or a fluorine atom, R12 represents a hydrogen atom

  gene. or a lower alkyl group (for example alkyl groups having 1 or 2 carbon atoms) and R 13 represents an alkyl group

  lower (for example, an alkyl group with 1 or 2 carbon atoms).

  bone) or a trifluoromethyl group.

  The cockroaches to which the present composition applies include, for example, the American cockroach (Periplaneta arn.ericana), the brown cockroach (Periplaneta brunnea), the sooty cockroach (Periplaneta fuliginosa), Nauphaeta cinerea and the German cockroach (Blattella germanica).

  Phenylxylylethane, which is one of the

  essential ingredients of the present invention,

  co-solvents to prepare a homogeneous solution of

  active ingredient (I) and polyfunctional isocyanate when a polyurethane wall is prepared by the method of

interfacial polymerization.

  As cosolvents, various organic solvents can be used as described in Japanese Patent Application Laid-open No. 55-38325, but those having a high flash point and having a mild odor are preferred. point of view of the

  safety and to prevent danger.

  Table 1 shows the flashpoint and odor level of various organic solvents described in Japanese Patent Application Laid-open No. 55-38325 and phenylxylylethane used in

  the present invention. It is clear that the phenomenon

  Nylxylylethane has such a high flash point and has such a low odor that it is particularly suitable

  as cosolvent. In addition, when comparing phenyl-

  xylylethane to diethyl phthalate, this is preferred to it from the point of view of cost and safety.

Table 1

  Point Name of organic lightning solvent Odor

O .__ _ _ _ _ _ _ _ _ _ _ _ _ (C)

  Xylene Strong Toluene 4 Idem Hexane -26 Idem hReptane -4 Idem Carbon tetrachloride - Idem Chloroform - Idem Methyl Isobutyl Ketone 23 Idem Methyl Ethyl Ketone Ldem Diethyl Phthalate 152 Low Normal Butyl Acetate 22 Medium Phenylxylylethane 152 Low

  Surprisingly, the micro-composition

  encapsulated of the active ingredient (I) prepared using

  phenylxylylethane as cosolvent is effective

  residual city to control cockroaches better than the microencapsulated composition of the active ingredient (I) prepared using other organic solvents such as methyl isobutyl ketone and cyclohexanone or

without using an organic solvent.

  When the microencapsulated composition of the ingredient

  active ingredient (I) with a polyurethane wall is used to control cockroaches, the effectiveness

  residue against cockroaches is likely to be

  served for a prolonged period only in micro-

  encapsulating the active ingredient (I) and phenylxylyl

  ethane in a microcapsule with a poly-

  urethane which has an average particle diameter of not more than 80 microns, a wall thickness which

  not more than 0.3 micron and a ratio of

  average meter of particles at the wall thickness which

is between 100 and 400.

  Microencapsulation is carried out, for example, by the process of dispersing a solution

  hydrophobic material containing a polyfunctional isocyanate, the

  active ingredient (I) and phenylxylylethane in a solution

  An aqueous solution containing a water-soluble polymer as a dispersing agent in the form of droplets and then allowing a polymerization reaction to be carried out on a polyol having at least two hydroxyl groups. When the encapsulation reaction is complete, the resulting suspension of capsules is diluted with water so as to obtain a desired concentration and, if

  necessary, a stabilizing agent is added to the suspension

  to obtain a stable formulation in suspension.

  As polyalcohols having at least two OH groups, mention may be made, for example, of ethylene glycol,

  propylene glycol, butylene glycol, hexanediol, hep-

  tanediol, dipropylene glycol, triethylene glycol,

  glycerine, resorcinol and hydroquinone. As iso-

  polyfunctional cyanate, may be mentioned for example

  toluene diisocyanate, hexamethyl diisocyanate,

  lene, adducts of toluene diisocyanate and trimethylolpropane, self-condensed products of hexamethylene diisocyanate, SUMIDUR L (supplied by Sumitomo-Bayer Urethane Co., Ltd.) and SUMIDUR N (supplied

  by Sumitomo-Bayer Urethane Co., Ltd.).

  The dispersing agents used to disperse a hydrophobic solution containing the active ingredient (I), phenylxylylethane and a polyfunctional isocyanate, include, for example, natural polysaccharides, such as

  gum arabic, semi-synthetic polysaccharides

  such as carboxymethylcellulose and methyl-

  cellulose, synthetic polymers such as polyvinyl alcohol and fine inorganic powders such as magnesium silicate and aluminum. It can be used

  be alone or in combination of two or more.

  When the dispersibility is low, it can be improved by adding a known voltage-active agent, as indicated

  in H. Horiguchi, "Synthetic Surface Active Agent".

  As suspension stabilizers, for a suspension with capsules, the water-soluble polymers listed above can be used as dispersing agents, as such, but if necessary, can be used as the

  thickening agents one or more polysaccharides

  such as xanthan gum and locust bean gum, semi-synthetic polysaccharides such as

  carboxymethylcellulose, synthetic polymers,

  such as sodium polyacrylate and fine

  minerals such as magnesium silicate and

aluminum.

  The active ingredient (I) used in the present invention includes geometric isomers and, furthermore,

  optical isomers derived from the presence of carbon

  do asymmetrical as well as their mixtures.

  Typical examples of active ingredients

(I) are as follows.

  (RS) -2- (4-chlorophenyl) -3-methylbutyrate from (RS) -a-

  cyano-3-phenoxybenzyl (fenvalerate),

  (S) -α-cyano- (S) 2- (4-chlorophenyl) -3-methylbutyrate

3-phenoxybenzyl (esfenvalerate),

  2,2,3,3-tetramethylcyclopropanecarboxylate (RS) -

  α-cyano-3-phenoxybenzyl (fenpropathrin), (1R) -cis, 3-phenoxybenzyl transchrysanthemate (d-phenothrin),

  (1R) -cis, (RS) -a-cyano-3- trans-chrysanthemate

phenoxybenzyl (cyphenotrin),

  (1RS) -cis, trans-3- (2,2-dichlorovinyl) -2,2-dimethyl-

  3-phenoxybenzyl cyclopropanecarboxylate (permethrin), (1R) -cis, trans-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropanecarboxylate acyano-3-phenoxybenzyl (cypermethrin),

  (1R) -cis, trans-3- (2,2-dibromovinyl) -2,2-dimethyl-

  α-cyano-3-phenoxybenzyl cyclopropanecarboxylate (deltamethrin), 2- (4-ethoxyphenyl) -2-methylpropyl-3-phenoxy benzyl ether (ethofenprox), and

  (1R) -cis-2,2-dimethyl-3- (1,2,2,2-tetrabromoethyl) -

  (S) -α-cyano-3-phenoxybenzyl cyclopropanecarboxylate

(Tralométhrin).

  If necessary, one can also add

  synergistic agents such as piperonyl butyrate and stabilizers such as

  BHT (2,6-di-t-butyl-4-methylphenol).

  When the amount of phenylxylylethane added is too small, the efficiency is insufficient and when it is too large, the concentration of the active ingredient decreases. For this reason, an amount of phenylxylylethane of 0.2 to parts per weight per part by weight of the ingredient is usually added.

active (I).

  The average particle diameter of microcapsules

  is determined by the nature and concentration

  dispersion agent used for dispersion

  and the degree of mechanical agitation during the dispersion.

  To measure the average diameter of the particles, it is possible to use for example the coulter counter model TA-II

(available at Nikkaki).

  The wall thickness of the microcapsule varies with the volume ratio of the core material to the wall-forming material and is obtained

  by the following approximate equation.

  Thickness = wcx d WC pw 6 in which d = average diameter of the microcapsule particles, wc = weight of the material forming the core, Ww = weight of the material forming the wall, pw = density of the material forming the wall,

  pc = density of the material forming the core.

  The thickness of the wall is calculated in the pre-

  invention using the equation above.

  The present position, before being applied, is usually diluted several times to several hundred times with water, although it depends on

  the nominal content of the active ingredient, then the

  diluted position is applied by a conventional device

  than spraying. Dosages, which depend on the

  the nature of the active ingredient, are usually included

  between 10 and 1000 mg of active ingredient per m2.

  The invention will be explained in more detail by the following examples, by comparative examples

and by the test examples.

Example 1

  To 100 g of kyphenothrin were added 10 g of "SUMIDUR" L (as indicated above) and 100 g of "HISOL" SAS-296 (1-phenyl-1-xylylethane prepared by Nippon Petrochemicals Co.) and shaken. until a uniform solution is obtained. This solution is added to 350 g of an aqueous solution containing 5% by weight of gum arabic as dispersing agent, and stirring is carried out for several minutes using a "T.K. autohomomixer". (trademark of Tokushukika Kogyo Co.) operating at room temperature, until formation of microdroplets. The rotation speed is 8000 rpm. 10 g of ethylene glycol are then added to the dispersed solution and the reaction is allowed to proceed with gentle stirring in a

  bath at a constant temperature of 60 C for 24 hours

  res, to obtain a suspension of a micro-

  encapsulated. Water is added to the suspension to obtain a total weight of 1000 g and to obtain a suspension of

  microcapsules in which 10% by weight of kyphosphoric acid

  thrin is encapsulated (composition present (1)).

  The microcapsule obtained has a mean particle diameter of 20 microns, a thickness of the wall of

  0.11 micron and a ratio of average particle diameter

  at the thickness of the wall of 182.

Example 2

  Example 1 is repeated, except that the quantity

  "SUMIDUR" L (as indicated above) becomes equal to 6 g, which makes it possible to obtain a suspension of microcapsules in which 10% by weight of kyphenothrin

  are encapsulated (composition present (2)).

  The microcapsules obtained have an average particle diameter of 19 microns, a thickness of the wall

  0,06 micron and a ratio of the average diameter of the

  to the wall thickness of 317.

Example 3

  Example 1 is repeated, except that the quantity

  "SUMIDUR" L becomes equal to 8 g and that the speed of

  rotation of the T.K. autohomomixer (as indicated by

  above) is 6500 rpm, to obtain a suspension of microcapsules in which 10% by weight of kyphenothrin is encapsulated (composition

present (3)).

  The microcapsules obtained have a mean particle diameter of 30 microns, a thickness of the wall

  0.14 micron and a ratio of the mean diameter of the

  particles at the wall thickness of 214.

Example 4

  Example 1 is repeated, except that the quantity

  "SUMIDUR" L (as indicated above) becomes equal to 5 g and that the rotational speed of T.K. homomixer (as indicated above) becomes equal to

  4700 revolutions / minute, which makes it possible to

  microcapsules in which 10% by weight of

  kyphenothrin are encapsulated (present composition 4)).

  The microcapsules obtained have a mean particle diameter of 50 microns, a wall thickness of 0.14 microns and a ratio of the average diameter

  particles at the wall thickness of 357. -

Example 5

  Example 4 is repeated, except that

  rotational speed of the homomixer T.K.

  above) becomes equal to 4000 revolutions / minute, to obtain a suspension of microcapsules in which 10% in

  The weight of kyphenothin is encapsulated

sente (5)).

  The microcapsules obtained have a mean particle diameter of 70 microns, a wall thickness of 0.20 micron and a ratio of the average diameter of the particles.

  particles at the wall thickness of 350.

Example 6

  To 100 g of fenvalerate, 8 g of "SUMIDUR" L (as indicated above) and 100 g of J'HISOL "SAS-296 (as indicated above) are added.

  stir until a uniform solution is obtained; We add

  this solution to 350 g of an aqueous solution containing

  5% by weight of gum arabic as a dispersing agent

Afterwards, stirring is carried out for several minutes in the homomixer T.K. (as indicated above) at a rotation speed of 4700 rpm.

  minute while operating at room temperature until

  the microdroplets. Then we add to the solution

  10 g of ethylene glycol are dispersed and the reaction is allowed to proceed, while stirring gently in a bath at a constant temperature of 60 ° C. for 24 hours.

  to obtain a suspension of one. micro-composition

  encapsulated. Water is added to the suspension to obtain

  a total weight of 1000 g and a suspension of

  capsules in which 10% by weight of fenvalerate are

  encapsulated (composition present (6)).

  The microcapsules obtained have a mean particle diameter of 50 microns, a thickness of the wall

  0,22 micron and a ratio of the average diameter of the

  to the wall thickness of 227.

Example 7

  To 100 g of d-phenothrin was added 7 g of "SUMIDUR" L (as indicated above and 20 g of "HISOL" SAS-296 (as indicated above) and shaken until

  obtaining a uniform solution. We add this solution

  200 g of an aqueous solution containing 5% by weight of gum arabic as dispersing agent, followed by stirring for several minutes in a homomixer TK (as indicated above), at 6000 rpm, operating at room temperature

  until formation of microdroplets. Then, to the solution

  dispersed, 12 g of ethylene glycol are added and

  let the reaction unfold, while gently shaking

  in a constant temperature bath of 70 ° C

  for 18 hours to obtain a suspension of a

microencapsulated position.

  To the suspension is added an aqueous solution containing 0.6% by weight of xanthan gum, for

Z625074

  obtain a total weight of 500 g and a suspension of microcapsules in which 20% by weight of d-phenothrin

  is encapsulated (composition present (7)).

  The microcapsules obtained have a mean particle diameter of 30 micron, a wall thickness of 0.2 microns and a ratio of the average particle diameter

at the wall thickness of 150.

Example 8

  To 100 g of kyphenothrin was added 12 g of "SUMIDUR" L (as indicated above) and 50 g of "HISOL" SAS-296 (as indicated above) and stirred until a uniform solution. This solution is added to 300 g of an aqueous solution containing% by weight of gum arabic as dispersing agent, followed by stirring for several hours.

  minutes in a T.K. homomixer (as indicated below).

  above) rotating at 8500 rpm, operating at the

  room temperature until microgout-

  slacks. 15 g of ethylene glycol are then added to the dispersed solution and the reaction is allowed to proceed while stirring gently in a constant temperature bath of 500 ° C. for 40 hours to obtain a

  suspension of the microencapsulated composition.

  To the suspension is added an aqueous solution containing 20% by weight of neutralized "AGRISOL" FL-100 (Kao Soap Co., Ltd.), to obtain a total weight of 1000 g and a suspension of microcapsules in which

  % by weight of kyphenothrin is encapsulated (

present (8)).

  The microcapsules obtained have a mean particle diameter of 20 microns, a wall thickness of 0.18 microns and a ratio of the average diameter

  particles at the wall thickness of 111.

Example 9

  To 50 g of fenvalêrate is added 8 g of "SUMIDUR" L (as indicated above) and 150 g of "HISOL" SAS-296 (as indicated above) and shaken until This solution is added to 350 g of an aqueous solution containing 5% by weight of gum arabic as a dispersing agent, followed by stirring for several minutes in the homomixer TK (as indicated). above)

  turning at 6500 rpm, operating at the same temperature

  ambient temperature until formation of the microdroplets.

  Then, to the dispersed solution, 20 g of propylene

  the glycol and allow the reaction to proceed, while stirring gently in a bath at a constant temperature of 60 C for 24 hours to obtain a suspension

of a microencapsulated composition.

  To the suspension is added an aqueous solution containing 0.4% by weight of xanthan gum and 0.8% by weight of magnesium aluminum silicate to obtain a total weight of 1000 g and a suspension of microcapsules in which 5% by weight of fenvalerate

  is encapsulated (composition present (9)).

  The microcapsules obtained have a mean particle diameter of 30 microns, a thickness of the wall of

  0.13 micron and a ratio of average particle diameter

  to the wall thickness of 231.

Example 10

  Example 8 is repeated, except that we use

  read 7 g of "SUMIDUR" N (as indicated above) instead of 12 g of "SUMIDUR" L (as indicated above and that the rotation speed becomes 4700 rpm) for obtain a suspension of microcapsules in which 10% by weight of kyphenothrin is encapsulated

(present composition (10)).

  The microcapsules obtained have a mean particle diameter of 50 microns, a wall thickness of 0.28 micron and a ratio of the average diameter of the particles.

  particles at the wall thickness of 179.

Example 11

  Example 8 is repeated except that 4 g of "SUMIDUR" L (as indicated above) and 4 g of "SUMIDUR" T-80 (toluene diisocyanate prepared from Sumitomo-Bayer Urethane Co., Ltd.) instead of 12 g of "SUMIDUR" L (as indicated above), obtaining a microcapsule suspension in which 10%

  weight of cyphenothrin is encapsulated (composition

feels (11).

  The microcapsules obtained have a mean particle diameter of 21 microns, a thickness of the wall of

  0.16 microns and a ratio of average particle diameter

  to the thickness of the wall of 131.

  EXAMPLE 12 To 10 g of permethrin was added 10 g of "SUMIDUR" L (as indicated above and 150 g of "HISOL" SAS-296 as indicated above and stirred until This solution is added to 400 g of an aqueous solution containing 5% by weight of gum arabic and 3% by weight of ethylene glycol, followed by stirring for several minutes in the homomixer. TK (as indicated above) running at 4700 rpm, operating at room temperature, until microdroplets are formed.

  the reaction proceed, while stirring gently in a bath at a constant temperature of 70 C for 18 hours, to obtain a suspension of a microencapsulated composition. To the suspension, water is added to obtain a total weight of 1000 g and this suspension is diluted twice with an aqueous solution containing 0.4% by weight of xanthan gum and 1.0% by weight of sodium silicate. magnesium and aluminum, to obtain a microcapsule suspension in which 5% by weight of

  permethrin is encapsulated (composition present (12)).

  The microcapsules obtained have a mean particle diameter of 50 microns, a thickness of the wall of

  0.23 micron and a ratio of the average particle diameter

  the thickness of the wall of 217.

Example 13

  To 100 g of cypermethrin, 6 g of "SUMIDUR" L (as described above) and 80 g are added.

  of "HISOL" SAS-296 (as indicated above) to obtain

  create a uniform solution. This solution is added to 400 g of an aqueous solution containing 10% by weight of polyvinyl alcohol as dispersing agent, followed by stirring for several minutes.

  in a T.K. homomixer (as indicated above)

  at 2600 revolutions / minute, until formation of micro-

  droplets. Then, to the dispersed solution, we add

  8 g of ethylene glycol and the reaction is allowed to proceed.

  while stirring gently in a bath at a constant temperature of 60 C for 24 hours to obtain a

  suspension of a microencapsulated composition.

  Water is added to obtain a total weight

  of 1000 g and a suspension of microcapsules in the

  which 10% by weight of cypermethrin is encapsulated

(present composition (13)).

  The microcapsules obtained have a mean particle diameter of 16 microns, a wall thickness of 0.07 and a ratio of the average particle diameter to

the wall thickness of 229.

  Comparative Example 1 To 100 g of cyfenothrin was added 22 g of "SUMIDUR" L (as indicated above) and 100 g of "HISOL" SAS-296 (as indicated above, to obtain * This solution is added to 400 g of an aqueous solution containing 10% by weight of polyvinyl alcohol as a dispersing agent, followed by stirring for several minutes in a homomixer TK (as indicated above). ) turning to

  3500 rpm, until microgout-

  slacks. 20 g of ethylene glycol are then added to the dispersed solution and the reaction is allowed to proceed while stirring gently in a bath at a constant temperature of 60 ° C. for 24 hours to obtain a

  suspension of the microencapsulated composition.

  Water is added to obtain a total weight of 1000 g and a suspension of microcapsules in which 10% by weight of kyphenothrin is erapsulated.

(comparative composition (1)).

  The microcapsules obtained have a mean particle diameter of 10 microns, a wall thickness of 0.12 micron and a ratio of the average diameter of the particles.

  particles at the wall thickness of 83.

  Example 1 is repeated, except that the quantity

  "SUMIDUR" L (as indicated above) becomes 3.5 g, the rotation speed TK becomes 4700 rpm, obtaining a suspension of microcapsules in which 10% by weight of kyphenothrin is encapsulated (comparative composition (2)). The microcapsules obtained have a mean particle diameter of 50 microns, a wall thickness of 0.1 micron and a ratio of the average diameter of the particles.

  particles at the wall thickness of 500.

  Comparative Example 3 6 g of "SUMIDUR" L (as mentioned above) was added to 100 g of kyphenotrin to obtain a uniform solution. This solution is added to 400 g of an aqueous solution containing 10% by weight of polyvinyl alcohol as a dispersing agent, followed by stirring for several minutes in a homomixer TK (as indicated above). ) turning

  at 2700 rpm, until microgout-

  slacks. Then, to the dispersed solution, 6 g of ethylene glycol are added and the reaction is allowed to proceed while stirring gently in a bath at a constant temperature of 60 ° C. for 24 hours to obtain

  suspension of the microencapsulated composition.

  Water is added to the suspension to obtain

  a total weight of 1000 g and a microcap suspension

  in which 10% by weight of kyphenothrin is

  encapsulated (comparative composition (3)).

  The microcapsules obtained have an average particle diameter of 15 microns, a wall thickness of 0.11 micron and a ratio of the average diameter of the particles.

  particles at the wall thickness of 136.

  Comparative Example 4 Example 6 is repeated, except that methyl isobutyl ketone is used instead of "HISOL" SAS-296 (as indicated above), obtaining a suspension.

  of microcapsules in which 10% by weight of fenva-

  lerate is encapsulated (comparative composition (4)).

  The microcapsules obtained have a mean particle diameter of 50 micron, a wall thickness of 0.21 microns and a ratio of the average diameter

  particles at the wall thickness of 238.

  Comparative Example 5 Example 6 was repeated except that acetophenone was used in place of the SAS-296 HISOL (as indicated above) to obtain a suspension of microcapsules in which 10% by weight of fenvalerate

  is encapsulated (comparative composition (5).

  The microcapsules obtained have a mean particle diameter of 50 microns, the wall thickness of 0.23 micron and the diameter ratio of the average diameter

  particles at the wall thickness of 217.

  Comparative Example 6 Example 6 is repeated except that cyclohexanone is used in place of SAS-296 "HISOL" (as indicated above) to obtain a suspension of microcapsules in which % by weight of fenvalerate is encapsulated (comparative composition (6)). The microcapsules obtained have a mean particle diameter of 50 microns, a wall thickness of 0.22 micron and a ratio of the average diameter of the particles.

  particles at the wall thickness of 227.

Comparative Example 7

  4 g of "SUMIDUR" L (as indicated below) are added

  above) to 100 g of heated fenvalerate to obtain a uniform solution. This solution is immediately poured into 350 g of a heated aqueous solution containing 5% by weight of gum arabic as dispersing agent, followed by stirring for several minutes in a T.K. homomixer (as indicated above).

  rotating at 4800 rpm, until formation of micro-

  droplets. 6 g of ethylene glycol are then added to the dispersed solution and the reaction is allowed to proceed while stirring gently in a bath at a constant temperature of 600 ° C. for 24 hours to obtain a

  suspension of a microencapsulated composition.

  Water is added to the suspension to obtain

  a total weight of 1000 g and a microcap suspension

  sules in which 10% by weight of fenvalerate is

  encapsulated (comparative composition (7)).

  The microcapsules obtained have a mean particle diameter of 50 microns, a wall thickness

  0,23 micron and a ratio of the average diameter of the

  particles at the wall thickness of 217.

  Test Example 1 Each of the present composition (6) and comparative compositions (4) to (6) are placed in a 100 cm3 beak and an olfactory test is carried out on a 100 cm beaker and an olfactory test is performed on whether or not the compositions have the odor of a solvent. There are 12 people who are not given any information on the names of the solvents used for the preparation of the microcapsules. The results are shown in Table 2.

Table 2

  (Solvent odor test) Number of persons Composition tested that detect the odor of a solvent Composition present (6) 1 Comparative composition (4) 10 Comparative composition (5) 10 Comparative composition (6) 10 This means that all people detect solvent odor for comparative compositions

  in which the solvent used is methyliso-

  butyl ketone, acetophenone or cyclohexanone, while only one person detects the solvent odor for the present composition (6) in which one uses

phenylxylylethane.

Test example 2

  Twenty times with water each of the

  tested in Table 3 and sprayed uniformly

  each of the compositions diluted on a panel against

  plated 15 cm x 15 cm at a rate of 50 ml / m. After drying the treated plywood panel for 2 hours, a plastic ring of 13 cm in diameter and 5 cm in height is placed on the treated panel (to prevent leakage, the inner surface is coated with butter) and confines a group of ten German cockroaches that are in contact with the treated panel for 2 hours. The cockroaches are transferred to a plastic cup containing water and

  food and we see the mortality 3 days later.

  In addition, mortality is observed using the same surfaces that were sprayed after

flow of 2, 4 and 8 weeks.

Table 3

  Mortality of the German cockroach (repeated 3 times) Diaer m n Duration (week) of treatment Compoition Average diameter Easer Mean diameter Mean diameter Thickness e by the composition tested and Composition. particles / tested wall particles mortality thickness (%) 72 hours after test thickness of (Pm) (m wall 2 4 8 Composition present (1) 20 0.11 182 100 100 100 100 present (I)

"(2) 19 0.06 317 100 100 100 90

"(3) 30 0.14 214 100 100 100 94

"(4) 50 0.14 357 100 100 100 83

"(5) 70 0.20 350 100 100 100 80

  Composition Composition 10 0.12 83 100 100 70 50 comparative (1)

"(2) 50 0.10 500 100 67.47 47

(3) (1) 15 0, 11 136 100 87 69 52

  () Phenylxylylethane is not used.

  Test Example 3 Each of the compositions tested and listed in Table 4 was diluted forty-fold with water and each dilution was applied to a plywood panel 15 cm x 15 cm at 50 ml / m 2. After drying

  for 2 hours the treated panel is placed on the panel.

  a plastic ring 13 cm in diameter and 5 cm in height (to prevent cockroaches from escaping, the inner surface is coated with butter) and contains a group of ten German cockroaches which

  are in contact with the treated panel for 2 hours.

  The cockroaches are transferred to a plastic cup.

  tick with water and food and

mortality 3 days later.

  In addition, mortality after treatment is

  for 2, 4 and 8 weeks using the same

application surfaces.

Table 4

  Mortality of the German cockroach (repeated 3 times) Diatre my Duration (week) of treatment Average D iameter EDa trmoe Cpsit Average diameter Thickness by the tried and tested composition of the particles of the thick wall Urs Solvsn mortality (%) 72 hours after test ( 11M) thickness of used wall 2 4 8 Composition present 50 0.22 227 Phenylxylyl 100 100 80 (6) ethane (6) Comparative composition 50 0, 21 238 Methyliso- 100 90 67 53 (4) .butylketone

(5) Aceto

  "(5) 50 0.23 217 phenone 100 93 83 53 (6) 50 0.22 227 Cyclohexa 100 100 70 67 none

"(7) 50 0.23 217 - 100 67 50 43

r.i

Claims (8)

  1. Microencapsulated composition to fight   against cockroaches, characterized in that   xylylethane and at least one of the insecticidal compounds defined below are encapsulated in microcapsules having a polyurethane wall which have a mean particle diameter of not more than 80 microns, a wall thickness which does not exceed is not greater than 0.3 micron and a ratio of the average particle diameter to   the thickness of the wall from 100 to 400, the insect compound   ticide being selected from compounds of formula X I 0 Y-CH - CH   wherein R 1 represents a hydrogen atom or a fluorine atom, X represents a hydrogen atom. or a cyano group, and Y represents a group of formula R2 0 C - CH R CH3 CH3 CH3 CH3 3 / R1 / CH CH - C -O - or - Il R12 R1 C-CH2-Z- 113   Wherein R2 represents a hydrogen atom or a methyl group; when R2 is a hydrogen atom, R3 represents a group of formula R4 R6   -CH = C or a group of formula \ C -CH-, 1 5 7, - "8 19 R R7 R R   in which R4 represents a methyl group, a chlorine atom, a bromine atom or a fluorine atom,   R5 represents a methyl group, a trifluoro-   methyl, a chlorine atom, a bromine atom or a R 7 R8 9   fluorine atom, R, R7, R8 and R9, which are identical or different, represent a chlorine atom, an atom   of bromine or a fluorine atom and, when R2 is a group   methyl, R3 represents a methyl group, R10 represents   feels a chlorine atom, a bromine atom, an atom   of fluorine, a trifluoromethoxy group, a difluoro-   romethoxy or a 3,4-methylenedioxy group, Z represents an oxygen atom or a -CH2- group, R1l represents a lower alkoxy group, a chlorine atom, a bromine atom or a fluorine atom, R12 represents an atom of hydrogen or a lower alkyl group, and R13 represents a lower alkyl group or a group R represents a lower alkyl group or a trifluoromethyl group.   2. The composition of claim 1, wherein   characterized in that the insecticidal compound is (1R) -   cis, (RS-) - α-cyano-3-phenoxy-transchrysanthemate benzyl.   3. The composition of claim 1, wherein   in that the insecticidal compound is (RS) -2-   (RS) -α-cyano-3 (4-chlorophenyl) -3-methylbutyrate phenoxybenzyl.   4. The composition of claim 1, wherein   characterized in that the insecticidal compound is (1R) -   cis, 3-phenoxybenzyl trans-chrysanthemate.   5. The composition of claim 1, wherein   in that the insecticidal compound is (IRS> -   cis, trans-3- (2,2-dichlorovinyl) -2,2-dimethylcyclopropane 3-phenoxybenzyl carboxylate.   6. Composition according to one of the claims   preceding, characterized in that the amount of phenylxylyléthane represents from 0.2 to 5 parts by weight   per part by weight of the insecticidal compound.   7. Method for combating cockroaches,   it consists in applying the composition   according to claim 1 to cockroaches.   8. Process for the preparation of the microencapsulated composition for combating cockroaches according to claim 1, characterized in that it consists in dispersing a solution containing phenylxylylethane, at least one of the insecticidal compounds defined in claim 1 and a polyfunctional isocyanate having at least two isocyanate groups in an aqueous solution containing a dispersing agent and a polyol having   at least two hydroxy groups and then submit the   persion at an interfacial polymerization reaction.